1 / 3 3 / 5 7 / 9... 15 / 17. According to this rule, what is the nth number I just forced junior high school students

1 / 3 3 / 5 7 / 9... 15 / 17. According to this rule, what is the nth number I just forced junior high school students

The nth number is (2 ^ n-1) / (2 ^ n + 1)